Blood pressure (BP) measures force applied to the walls of arteries as a heart pumps blood through the body. The pressure is determined by the force and amount of blood pumped, and the size and flexibility of the arteries. Systolic and diastolic arterial BP is not static but undergoes natural variations from one heartbeat to another and throughout the day (in a circadian rhythm). Blood pressure variation and changes may be utilized for patient health status monitoring. Some recent studies successfully use power spectra (such as indicating Low or High Frequency bandwidth) to analyze blood pressure variability for detecting cardiac abnormality. However, blood pressure variability may be affected by many factors, such as age, disease, breathing control, physical conditions and neurological status.
There are two types of blood pressure: systolic and diastolic. Systolic blood pressure comprises pressure of the blood when the heart has imparted the maximum pressure. Diastolic blood pressure is the pressure when the heart is in the resting phase. Blood pressure (BP) is the pressure exerted by circulating blood on the walls of blood vessels, and is a principal vital sign. During each heartbeat, BP varies between a maximum (systolic) and a minimum (diastolic) pressure. The mean BP decreases as the circulating blood moves away from the heart through arteries and has its greatest decrease in the small arteries and arterioles, and continues to decrease as the blood moves through the capillaries and back to the heart through veins. The systolic pressure and diastolic pressure may show different kinds of variation and trends for different cardiac events or arrhythmias and pressure mean value may not detect cardiac conditions.
Noninvasive auscultatory and oscillometric measurements are simpler and quicker than invasive measurements have virtually no complications, and are less unpleasant and painful for the patient. However, noninvasive methods may yield lower accuracy and small systematic differences in numerical results. Non-invasive measurement methods are more commonly used for routine examinations and monitoring. Systolic and diastolic arterial BPs change in response to stress, nutritional factors, drugs, disease, exercise, and momentarily from standing up. Sometimes the variations are large. Hypertension refers to arterial pressure being abnormally high, as opposed to hypotension, when it is abnormally low. Along with body temperature, respiratory rate, and pulse rate, BP measurements are the most commonly measured physiological parameters. However known pressure data analysis typically fails to comprehensively extract pathology related pressure information and exclude non-pathology data and noise. This results in a high rate of false alarm in cardiac pathology detection.
Known blood pressure analysis usually tracks the absolute value of systolic and diastolic blood pressure measurements and mean calculations discretely (e.g., Measuring Non-invasive blood pressure every 5 minutes), which may fail to extract sufficient pathology and event information. Known pressure analysis may also fail to exclude noise factors (non-related pressure variation factors, such as respiration) which may distort detection and characterization accuracy of cardiac events or arrhythmias. Further, known blood pressure analysis usually does not differentiate the results of different pressure analysis, such as systolic, diastolic, EoS (end of systolic pressure), EoD (end of diastolic pressure) and fail to bridge cardiac arrhythmia diagnosis and status characterization with pressure calculation based multi-parameter analysis. A system according to invention principles addresses these deficiencies and related problems.